Preservation of water quality in accumulation Lake Rovni: the estimate of the emission of phosphorus from inundation area

The emission of phosphorus from various ecochemical types of soil (arable land, forest, meadow and orchard) was investigated in order to preserve the quality of water in a future accumulation lake (54 millions cubic meters and 230 ha) Rovni near Valjevo (Serbia and Montenegro). Samples were taken from three depths: 0-10, 10-20 and 20-30 cm. In order to extract different forms of phosphorus (known as NH4Cl-P or available-P, Al-P, Fe-P, reducible-P, occluded-P and Ca-P) all samples were subjected to sequential extraction according to the modified method of Chang and Jackson. Most of phosphorus was bound to iron. This fraction contained more than 80% of inorganic P and it is expected that in the future accumulation lake the chemodynamics of phosphorus and iron will be closely related. This conclusion is in agreement with the results of two independent extraction procedures. Inorganic phosphorus is in a greater extent associated with Si than with Al. These results are important for the provision of good water quality in the future accumulation Lake Rovni near Valjevo (Serbia and Montenegro).